Planetary rotor machine with synchronizing mechanism

ABSTRACT

Various examples of planetary rotor machines and synchronizing mechanisms are provided. In one example, a planetary rotor machine comprises a plurality of helical rotors for compressing or expanding a fluid. Each of the helical rotors is configured to rotate about a rotor rotational axis, and each of the rotor rotational axes is equally spaced from a central axis of the planetary rotor machine. A rotor shaft is fixedly coupled to each of the helical rotors and extends axially along the rotor rotational axis. A rotor crank is coupled to each of the rotor shafts and comprises a rotor crank arm that extends away from the rotor rotational axis. Each rotor crank arm comprises a rotor crankpin at a distal end that is laterally spaced from the rotor rotational axis. A synchronizing plate is rotatably coupled to each of the rotor crankpins for non-rotative epicyclic oscillation with respect to the plurality of rotor shafts and the helical rotors. A driver crank is rotatably coupled to a central bearing in a geometric center of the synchronizing plate. A driveshaft is fixedly coupled to the driver crank and located coaxial with the central axis of the planetary rotor machine

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent Application Ser. No. 61/914,221, filed on Dec. 10, 2013 and entitled PLANETARY ROTOR MACHINE ROTOR CRANK LINKAGE, the entirety of which is hereby incorporated by reference for all purposes.

FIELD

The present disclosure relates generally to the field of planetary rotor machines.

BACKGROUND

Multi-rotor planetary rotor machines may be utilized as positive displacement devices in a variety of applications. A planetary rotor machine typically employs 3 or 4 rotors equally disposed around a central machine axis. All of the rotors have the same shape and rotate in the same direction. Together, the multiple rotors cooperative to form an internal working volume, or cavity, bounded by the rotors themselves.

Planetary rotor machines utilize rotors having lobes with an axial helical twist to create an internal “progressive cavity” that conducts fluid along the machine center axis in a manner similar to a screw auger. Fluid (gas, liquid, or multiphase) is introduced at one end of the rotor assembly from a first pressure regime, and is transported by the rotor-formed cavity to the opposite end for discharge into a different pressure regime. In this manner the planetary rotor machine operates as an expander or compressor to either produce or extract shaft power.

Axial walls of the cavity are provided by flat, stationary head plates, or manifolds, that abut opposite ends of the rotor assembly. In this manner, and unlike conventional twin screw machines, planetary rotor machines do not require a precision encasement surrounding the rotor assembly. Rather, the cavities are formed by the meshing rotors in cooperation with the flat manifolds abutting the rotor ends.

The mutually engaging planetary rotors constitute the radial walls of the progressive cavity, without requiring an external housing. The adjacent surfaces of meshing rotors are non-contacting and separated by a small gap. The volumetric efficiency of a planetary rotor machine, as a function of cavity leakage via inter-rotor gaps, is an important parameter affecting overall machine efficiency. Leakage arising from the finite inter-rotor gap may constitute the primary loss mechanism affecting machine efficiency.

Unidirectional rotor rotation produces high relative velocities between adjacent rotor surfaces at their meshing points. Frictional issues that may arise from physical contact of adjacent meshing rotors may be largely mitigated by holding tight non-contact running clearances between rotors, which in turn calls for precision dimensional tolerances of rotor contours and exacting angular synchronization during rotation of all rotors relative to one another. Accordingly, maximizing efficiency in a planetary rotor machine depends significantly upon minimizing cavity leakage, which in turn relies on precise angular synchronization of all rotors relative to one another during rotation.

In some prior planetary rotor machines, rotor synchronization has been accomplished via planetary rotor gears meshing with a central sun gear or internal ring gear to transfer torque from multiple rotors into a single main output/input shaft. However, meshed gears require a degree of intentional backlash or play to accommodate lubrication, machining non-symmetry, and rotational eccentricities. Such backlash limits the precise inter-rotor clearances that are desirable in planetary rotor machines. Accordingly, utilizing gear trains for rotor synchronization results in larger inter-rotor gaps and reduced machine efficiency. Further, in such planetary gear trains, inter-rotor synchronization utilizes two meshing points, thereby doubling the backlash of a single geared pair and further compromising rotor synchronization.

Some prior planetary rotor machines have attempted to achieve rotor synchronization via belts and pulleys. However, belt and pulley teeth are prone to deformation and alignment shift under varying torque loads. Additionally, variations in belt manufacturing results in non-uniform spacing between teeth and different size/shape teeth on a given belt. Accordingly, such belt and pulley systems have proven to be more problematic than gear train synchronization mechanisms.

Other prior attempts to synchronize rotors via roller chains and sprockets have proven to be problematic. Backlash in chain driven mechanisms causes problems similar to geared systems. Irregularities in chain manufacturing causes spacing discrepancies in chain linkages. Extended use of chain systems results in wear of chain and sprocket surfaces compounding backlash issues. Torque transfer via a chain and sprocket causes chains to stretch increasing backlash.

SUMMARY

Embodiments that relate to a planetary rotor machine are provided. In one embodiment, a planetary rotor machine comprises a plurality of helical rotors for compressing or expanding a fluid. Each of the helical rotors is configured to rotate about a rotor rotational axis, and each of the rotor rotational axes is equally spaced from a central axis of the planetary rotor machine. A rotor shaft is fixedly coupled to each of the helical rotors and extends axially along the rotor rotational axis.

A rotor crank is coupled to each of the rotor shafts and comprises a rotor crank arm that extends away from the rotor rotational axis. Each rotor crank arm comprises a rotor crankpin at a distal end that is laterally spaced from the rotor rotational axis. A synchronizing plate is rotatably coupled to each of the rotor crankpins for non-rotative epicyclic oscillation with respect to the plurality of rotor shafts and the helical rotors. A driver crank is rotatably coupled to a central bearing in a geometric center of the synchronizing plate. A driveshaft is fixedly coupled to the driver crank and located coaxial with the central axis of the planetary rotor machine.

Another embodiment relates to a 4-rotor synchronizing mechanism for a 4-rotor planetary rotor machine. The 4-rotor planetary rotor machine comprises 4 helical rotors for compressing or expanding a fluid and 4 rotor shafts. Each of the helical rotors is fixedly coupled to one of the rotor shafts and configured to rotate about a rotor rotational axis. Each of the rotor rotational axes is equally spaced from a central axis of the 4-rotor planetary rotor machine.

The 4-rotor synchronizing mechanism comprises 4 rotor cranks that are each coupled to one of the 4 rotor shafts, each of the rotor cranks comprising a rotor crank arm that extends away from the rotor rotational axis. Each of the rotor crank arms comprises a rotor crankpin at a distal end that is laterally spaced from the rotor rotational axis. A synchronizing plate comprises 4 bearings symmetrically oriented around a geometric center of the synchronizing plate at 90 degree intervals, with each of the bearings rotatably coupled to one of the 4 crankpins for non-rotative epicyclic oscillation of the synchronizing plate with respect to the 4 rotor shafts and the 4 helical rotors. A driver crank is rotatably coupled to a central bearing in the geometric center of the synchronizing plate. A driveshaft is fixedly coupled to the driver crank and located coaxial with the central axis of the planetary rotor machine.

Another embodiment relates to a 3-rotor synchronizing mechanism for a 3-rotor planetary rotor machine. The 3-rotor planetary rotor machine comprises 3 helical rotors for compressing or expanding a fluid and 3 rotor shafts. Each of the helical rotors is fixedly coupled to one of the rotor shafts and configured to rotate about a rotor rotational axis. Each of the rotor rotational axes is equally spaced from a central axis of the 3-rotor planetary rotor machine,

The 3-rotor synchronizing mechanism comprises 3 rotor cranks that are each coupled to one of the 3 rotor shafts. Each of the rotor cranks comprises a rotor crank arm that extends away from the rotor rotational axis. Each of the rotor crank arms comprises a rotor crankpin at a distal end that is laterally spaced from the rotor rotational axis. A synchronizing plate comprises 3 bearings symmetrically oriented around a geometric center of the synchronizing plate at 120 degree intervals, with each of the bearings rotatably coupled to one of the 3 crankpins for non-rotative epicyclic oscillation of the synchronizing plate with respect to the 3 rotor shafts and the 3 helical rotors. A driver crank is rotatably coupled to a central bearing in the geometric center of the synchronizing plate. A driveshaft is fixedly coupled to the driver crank and located coaxial with the central axis of the planetary rotor machine.

It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.

BRIEF DESCRIPTION OF THE FIGURES

The present disclosure will be better understood from reading the following description of non-limiting embodiments with reference to the attached drawings, wherein:

FIG. 1 shows a schematic view of one example use case for geothermal power generation using a planetary rotor machine.

FIG. 2 shows a perspective view of a 4-rotor planetary rotor machine utilizing a 4-rotor synchronizing mechanism according to one example of the present disclosure.

FIG. 3 shows a partial perspective view of the rotors and synchronizing mechanism of the planetary rotor machine of FIG. 2.

FIG. 4 shows an end view of the synchronizing mechanism of the planetary rotor machine of FIG. 2 excluding the driver crank

FIG. 5 shows an end view of the synchronizing mechanism of the planetary rotor machine of FIG. 2 including the driver crank

FIG. 6 shows a transverse cross-sectional view of the 4 rotors of the planetary rotor machine of FIG. 2 showing an orientation of the 4 rotors in which the cavity volume is minimized.

FIG. 7 shows a partial side view of the rotors and synchronizing mechanism of FIG. 3.

FIG. 8 shows a partial side view of rotors of a 4-rotor planetary rotor machine and a synchronizing mechanism according to another example of the present disclosure.

FIG. 9 shows a partial side view of rotors of a 4-rotor planetary rotor machine and a synchronizing mechanism according to yet another example of the present disclosure.

FIG. 10 shows a partial perspective view of the rotors of a 3-rotor planetary rotor machine utilizing a 3-rotor synchronizing mechanism according to another example of the present disclosure.

FIG. 11 shows an end view of the synchronizing mechanism of the planetary rotor machine of FIG. 10 excluding the driver crank

FIG. 12 shows an end view of the synchronizing mechanism of the planetary rotor machine of FIG. 11 including the driver crank

FIG. 13 shows a transverse cross-sectional view of the 3 rotors of the planetary rotor machine of FIG. 10 showing an orientation of the 3 rotors in which the cavity volume is maximized.

FIG. 14 shows a partial side view of the rotors and synchronizing mechanism of FIG. 10.

FIG. 15 shows a partial side view of rotors of a 3-rotor planetary rotor machine and a synchronizing mechanism according to another example of the present disclosure.

DETAILED DESCRIPTION

FIG. 1 shows one non-limiting example use case for geothermal power generation using a planetary rotor machine according to an example of the present disclosure. In this example, a planetary rotor expander 10 receives hot brine from a production well in a geothermal zone. The brine is received at an intake valve 20 in the saturated liquid state. The brine is isentropically flashed inside the expander 10 where temperature and pressure drop to condenser conditions while simultaneously extracting shaft work in the process. The rotors of the expander 10 are synchronized by a synchronizing mechanism 40 that also transmits power from the rotors' rotation to a driveshaft 30. The driveshaft 30 is coupled to generator 50 which produces electric power.

It will be appreciated that planetary rotor machines and corresponding synchronizing mechanisms of the present disclosure may be utilized in other power generation applications including, but not limited to, geopressure power production, waste heat applications, solar thermal and solar ponds, biomass, and other applications using thermal resources with sufficient heat capacity. Planetary rotor machines and corresponding synchronizing mechanisms of the present disclosure also may be utilized with any pressurized fluid, regardless of viscosity or temperature, to produce electric power instead of dissipation through pressure let-down valves. Examples include, but are not limited to, natural gas wellhead pressure letdown, grid sub-station pressure let-down, producing oil & gas wells, off-shore oil platforms, industrial processes, biomass refinement let-down, slurry (suspended particulate) pumping such as coal slurry, wood chip slurry, and biomass pumping, and high pressure pumping such as hydrofracking It will also be appreciated that that planetary rotor machines and corresponding synchronizing mechanisms of the present disclosure also may be utilized in a variety of compressor applications.

FIG. 2 shows a schematic illustration of a 4-rotor planetary rotor machine 100 and 4-rotor synchronizing mechanism 110 according to an example of the present disclosure. The planetary rotor machine 100 may be utilized for a variety of positive displacement applications in which a fluid is compressed or expanded within one or more cavities created by the helical rotors of the machine. For example, the planetary rotor machine 100 may receive pressurized fluid via an intake pipe 118 and an entry manifold 122. The entry manifold 122 may be configured to substantially prevent the fluid from bypassing the cavity created by the rotors of the machine.

Examples of manifolds for planetary rotor machines are discussed in U.S. Patent Application Publication No. 2014/0255232 entitled PLANETARY ROTOR MACHINE MANIFOLD, the disclosure of which is hereby incorporated by reference for all purposes.

As the rotors 114 of the machine 100 rotate, the space enclosed between the meshing rotors 114 forms a cavity that progresses axially during rotor rotation due to the helical axial twist of the rotor lobes. As the cavity progresses it forms a varying volume that is bounded by the rotors 114 themselves. This progressive cavity transports fluid (gas, liquid, or multiphase) along the machine center axis like a screw auger. A minimum helical twist of 180° may be utilized for a 4-rotor machine and a minimum helical twist of 120° may be utilized for a 3-rotor machine, as described in more detail below. A 4-rotor machine produces two complete volume cycles per revolution. A 3-rotor machine produces 3 complete volume cycles per revolution.

Fluid inducted via the intake pipe 118 travels inside the rotor-formed cavity along the machine center axis to the opposite, exit end where it discharges into a higher pressure region for a compressor, or into a lower pressure region for an expander. Accordingly, the process produces shaft power in an expander or extracts shaft power in a compressor.

When operating as an expander, the pressurized fluid drives rotation of the helical rotors 114 (partially shown) and produces shaft power. As described in more detail below, the rotors 114 are coupled to synchronizing mechanism 110 which in turn drives rotation of output driveshaft 154 that is connected to a generator (not shown). After passing through the cavities created by rotors 114, the pressurized fluid may be discharged through an exit manifold (not shown) at the rear of the machine 100.

In the example of FIG. 2, the planetary rotor machine 100 includes 4 helical rotors 114 (partially shown). In this example, the rotors 114 are contained within a housing 126. It will be appreciated that in other examples the planetary rotor machine may not utilize such a housing or may utilize a housing that partially encloses the rotors.

With reference also to FIGS. 3-6 and as described in more detail below, each rotor 114 is fixedly coupled to a rotor shaft 130 and configured to rotate about a rotor rotational axis 136. Each of the rotor shafts 130 and corresponding rotors 114 rotates in the same direction, shown in this example by action arrow A. As best seen in FIG. 6, each of the 4 rotor rotational axes 136 is equally spaced from a central axis 140 of the 4-rotor planetary rotor machine 100. FIG. 6 also illustrates the solid core 150 that extends co-axially with the machine central axis 140 through the cavity created by the rotors 114. The core 150 corresponds to a minimum cavity area that occurs when the major axes of all 4 rotors 114 orient radially with respect to the machine center, as shown in FIG. 6. Alternatively expressed, the core 150 is configured and sized to occupy substantially all of the volume between the 4 rotors when the rotors are oriented to minimize the volume of the cavity as shown in FIG. 6.

It will also be appreciated that the cross-sectional area of the solid core 150 formed by the converging rotor tips does not directly participate in machine function. The core 150 may comprise a solid, symmetric, 4-sided rod having opposing sides that are mirror images of one another. At least two partial cavities may be formed along the rotor length at any given instant. Thus it will be appreciated that a function of core 150 is to prevent axial leakage between successive cavities.

With reference again to FIGS. 2 and 3, each rotor shaft 130 is fixedly coupled to a rotor crank 160 that engages the synchronizing mechanism 110 which transmits rotor and shaft rotation to a driveshaft 154. Advantageously, and as described in more detail below, the synchronizing mechanism 110 couples all rotating elements in rigid angular alignment during rotation, irrespective of the differing locations of the rotational axis of individual rotors and the output driveshaft 154. Backlash problems associated with traditional gears or pulley/belt assemblies are eliminated by the synchronizing mechanism 110 to facilitate a level of synchronized precision for planetary rotor machines hitherto unattainable.

As shown in FIGS. 2-5 and 7, each rotor shaft 130 is fixedly coupled to a rotor crank 160. As best seen in FIGS. 3 and 4, each rotor crank 160 comprises a rotor crank arm 164 that extends away from the rotor rotational axis 136 of the corresponding rotor 114 to a distal end 170 of the rotor crank arm. A rotor crankpin 174 is located at the distal end 170 of each rotor crank arm 164. In this manner, the rotor crankpin 174 is laterally spaced from the rotor's rotational axis 136.

More particularly, each rotor crankpin 174 is centered on a rotor crankpin axis 178. As illustrated in FIG. 5, the throw of each rotor crank arm 164 corresponds to a radius 182 of each rotor crankpin axis 178 relative to the rotor rotational axis 136 of the corresponding rotor 114. In this example of synchronizing mechanism 110, each of the 4 rotor cranks 160 has an equal throw, wherein the radius 182 of each rotor crankpin axis 178 relative to the rotor rotational axis 136 of the corresponding rotor 114 is equal. In this manner and advantageously, during operation of the planetary rotor machine 100, each of the 4 rotor cranks 160 remains angularly fixed relative to one another. Further and as described in more detail below, each of the 4 rotor crankpins is rotatably coupled to a synchronizing plate 184 in a manner that produces non-rotative epicyclic oscillation of the plate with respect to the 4 rotor shafts 130 and 4 helical rotor 114.

In the example of FIGS. 2-5 and with reference also to FIG. 7, each rotor crank arm 164 comprises a straight neck 186 that extends parallel to a plane of rotation 188 of the rotor crank arm and connects a rotor crank base portion 192 at the rotor rotational axis 136 with the distal end 170 of the arm. As noted above, the rotor crankpins 174 located at the distal end 170 of the 4 rotor crank arms 164 are rotatably coupled to synchronizing plate 184. More particularly, the rotor crankpins 174 are rotatably coupled to 4 rotor crank bearings 196 that are symmetrically oriented around the geometric center 200 of the synchronizing plate 184 at 90 degree intervals. Each of the 4 rotor crank bearings 196 is equidistant from the geometric center 200 of the synchronizing plate 184.

In this manner, the synchronizing plate 184 traces a circular orbit with respect to the rotors 114 and without rotating about its geometric center 200 or otherwise. Alternatively expressed, the synchronizing plate 184 engages in non-rotative epicyclic oscillation with respect to the 4 rotor shafts 130 and 4 helical rotors 114. Accordingly, the rotors 14 are constrained to rotate in rigid synchronization, thereby enabling inter-rotor gaps that are significantly smaller than previously possible. In some examples, planetary rotor machines according to the present disclosure may utilize inter-rotor gaps on the order of 0.001 inches or less. Further, and in contrast to the gear train and belt/pulley systems of other mechanisms, the synchronizing mechanism 110 of the present disclosure enables such precise synchronization and minute gaps to be maintained over significant duty cycles at high speeds, such as 3600 RPM or higher which can produce centrifugal g-force loads in the range of 600 g.

With reference to FIGS. 3 and 7, a driver crank 220 includes a driver crankpin lobe 224 and a driver crankpin 228 centered on a driver crankpin axis 232. The driver crankpin lobe 224 and driver crankpin 228 are spaced laterally from the driveshaft rotational axis 236 of the driveshaft 154 such that the driveshaft rotational axis 236 is coaxial with the central axis 140 of the 4-rotor planetary rotor machine 100. The driver crankpin 228 is rotatably coupled to a central bearing 230 of the synchronizing plate 184. It will be appreciated that by rotatably coupling the driver crankpin 214 to the synchronizing plate 184 in this manner, the synchronizing mechanism 110 transfers the torque from the 4 rotors 114 into the single driveshaft 154.

Further and with reference to FIGS. 5 and 7, the synchronizing mechanism 110 is configured such that the radius 182 of each rotor crankpin axis 178 relative to the rotor rotational axis 136 of the corresponding rotor 114 is equal to the radius 240 of the driveshaft crankpin axis 232 relative to the driveshaft rotational axis 236. Accordingly, the throw of driver crank 220 is equal to the throw of each rotor crank arm 164.

With reference now to FIG. 8, in another example of a 4-rotor planetary rotor machine 800, a synchronizing mechanism 110′ includes rotor crank arms 810 having a spacer neck 820 that provides an additional offset for the synchronizing plate 184 in the z-axis direction from the plane of rotation 830 of the rotor crank arms. It will be appreciated that in the synchronizing mechanism 110 described above that utilizes rotor crank arms 164 having a straight neck 186, a maximum length of each rotor crank arm is limited by the need for sufficient clearance with adjacent rotor crank arms (See FIG. 7). Accordingly, in these examples the distance between adjacent rotor rotational axes 136 limits a maximum length of the rotor crank arms 164 and the corresponding throw of the arms.

As shown in the example of FIG. 8, angled rotor crank arms 810 include a spacer neck 820 that is angled with respect to a plane of rotation 830 of the rotor crank arms. The spacer neck 820 connects a rotor crank base portion 836 at the rotor rotational axis 840 with the distal end 844 of the rotor crank arm 810. As with the synchronizing mechanism 110 described above and shown in FIG. 7, rotor crankpins 174 located at the distal end 844 of the 4 rotor crank arms 810 are rotatably coupled to 4 rotor crank rotor crank bearings 196 that are symmetrically oriented around the geometric center 200 of the synchronizing plate 184 at 90 degree intervals. A driver crank 220′ is rotatably coupled to a central bearing in the center of the he synchronizing plate 184. A driveshaft 154 is fixedly coupled to the driver crank 220′ and located coaxial with the central axis of the planetary rotor machine 800.

Advantageously, the offset geometry of the spacer necks 820 of the angled rotor crank arms 810 enables increased crank throw length by allowing the distal end 844 of each arm to clear adjacent rotor rotational axes 840 and adjacent rotor cranks. Further, greater crank throw length decreases the forces experienced by the 4 rotor crank bearings 196 of the synchronizing plate 184. Such decrease in force may be described by the following equation:

t=r*F,   [1]

Where t=rotor shaft torque, r=length of crank throw, and F=force experienced at the distal end of the rotor crank.

Accordingly and for a given rotor shaft torque t, as the crank throw length r increases, the resulting force F on the rotor crank decreases. Advantageously, reducing the forces experienced by the rotor crank bearings 196 extends the life of the bearings and/or allows the use of smaller bearings in a given application. It will be appreciated that any suitable type of bearing may be utilized for the rotor crank bearings 196 and the central bearing 230 of the synchronizing plates described in the present disclosure. Examples of such bearing types include, but are not limited to, ball bearings, air bearings, journal bearings, and magnetic bearings.

In other examples, a synchronizing mechanism according to the present disclosure may utilize rotor crank arms having 2 or more angled portions that are each angled with respect to the plane of rotation of the rotor crank arm. With reference now to FIG. 9, in one example a 4-rotor planetary rotor machine 900 comprises a synchronizing mechanism 110″ that includes rotor crank arms 910 having a spacer neck 920 that includes 2 angled portions 924 and 928 that provide an additional offset for the synchronizing plate 184 in the z-axis direction.

The 2 angled portions 924 and 928 of spacer neck 920 are each angled with respect to a plane of rotation 830 of the rotor crank arms 910. The spacer neck 920 connects a rotor crank base portion 936 at the rotor rotational axis 940 with the distal end 944 of the rotor crank arm 910. As with the synchronizing mechanisms 110 and 110′ described above, rotor crankpins 174 located at the distal end 944 of the 4 rotor crank arms 910 are rotatably coupled to 4 rotor crank rotor crank bearings 196 that are symmetrically oriented around the geometric center 200 of the synchronizing plate 184 at 90 degree intervals. A driver crank 220″ is rotatably coupled to a central bearing in the center of the synchronizing plate 184. A driveshaft 154 is fixedly coupled to the driver crank 220″ and located coaxial with the central axis of the planetary rotor machine 900. In some examples, driver crank 220″ may include a counterweight 950 for load balancing.

Advantageously, by utilizing rotor crank arms having 2 angled portions 924 and 928, crank throw length may be further increased while maintaining a greater structural integrity of the rotor crank arm as compared to an arm having a single angled portion that creates a similar crank throw. Advantageously and as noted above, further increasing crank throw length correspondingly decreases the forces experienced by the 4 rotor crank bearings 196 of the synchronizing plate 184.

With reference again to FIGS. 3-5, in some examples each of the rotor cranks 160 may comprise a rotor crank counterweight lobe 260 that is spaced laterally from the corresponding rotor rotational axis 136 and located opposite to the rotor crank arm 164. To provide dynamic balancing, a rotor crank counterweight 264 may be coupled to the rotor crank counterweight lobe.

As noted above, the principles of the present disclosure may also be utilized in connection with a planetary rotor machine having 3 rotors that each embodies a 3-lobed rotor design. With reference now to FIGS. 10-14, in one example a planetary rotor machine of the present disclosure may comprise 3 rotors 1000 having rotational axes 1010 positioned at the 3 corners of an equilateral triangle. As shown in FIG. 13, the geometric center 1016 of the triangle corresponds to the machine center axis of the planetary rotor machine. As with the 4-rotor machine described above, a solid core (not shown) extends co-axially with the machine center axis 1016 through the cavity created by the rotors 1000. The core corresponds to a minimum cavity area that occurs when the tip of a lobe of each of the 3 rotors 1000 is nearest to the machine center axis 1016.

Each rotor 1000 is fixedly coupled to a rotor shaft 1020 and configured to rotate about a rotor rotational axis 1028. Each of the rotor shafts 1020 and corresponding rotors 1000 rotates in the same direction, shown in this example by action arrow B. As best seen in FIG. 13, each of the rotor rotational axes 1010 is equally spaced from the machine center axis 1016 of the 3-rotor planetary rotor machine.

Each rotor shaft 1020 engages the synchronizing mechanism 1030 via a rotor crank 1040 that transmits rotor and shaft rotation to a driveshaft 1034. Advantageously, and as with the synchronizing mechanism 110 described above, the synchronizing mechanism 1030 couples all rotating elements in rigid angular alignment during rotation, irrespective of the differing locations of the rotational axis of individual rotors and the output driveshaft 1034.

As shown in FIGS. 10-12 and 14, each rotor shaft 1020 is fixedly coupled to a rotor crank 1040. As best seen in FIG. 10, each rotor crank 1040 comprises a rotor crank arm 1044 that extends away from the rotor rotational axis 1028 of the corresponding rotor 1000 to a distal end of the rotor crank arm. A rotor crankpin 1050 is located at the distal end of each rotor crank arm 1044. In this manner, the rotor crankpin 1050 is laterally spaced from the rotor's rotational axis 1028.

With reference to FIG. 12, each rotor crankpin 1050 is centered on a rotor crankpin axis 1054. As with the 4-rotor synchronizing mechanism 110 described above, the throw of each rotor crank arm 1044 corresponds to a radius of each rotor crankpin axis 1054 relative to the rotor rotational axis 1028 of the corresponding rotor 1000. As shown in FIGS. 10-13, each of the 3 rotor cranks 1040 has an equal throw, wherein the radius of each rotor crankpin axis 1054 relative to the rotor rotational axis 1028 of the corresponding rotor 1000 is equal. In this manner and advantageously, during operation of the planetary rotor machine, each of the 3 rotor cranks 1040 remains angularly fixed relative to one another. Further and as described in more detail below, each of the 3 rotor crankpins is rotatably coupled to a synchronizing plate 1060 in a manner that produces non-rotative epicyclic oscillation of the plate with respect to the 3 rotor shafts 1020 and 3 helical rotor 1000.

As best seen in FIGS. 10 and 14, each rotor crank arm 1044 comprises a straight neck 1064 that extends parallel to a plane of rotation 1070 of the rotor crank arm and connects a rotor crank base portion 1074 at the rotor rotational axis 1028 with the distal end of the arm. As noted above, the rotor crankpins 1050 located at the distal end of the 3 rotor crank arms 1044 are rotatably coupled to synchronizing plate 1060. More particularly, the rotor crankpins 1050 are rotatably coupled to 3 rotor crank bearings 1078 that are symmetrically oriented around the geometric center 1082 of the synchronizing plate 1060 at 120 degree intervals. Each of the 3 rotor crank bearings 1078 is equidistant from the geometric center 1082 of the plate 1060.

In this manner and like the synchronizing plate 184 described above, the synchronizing plate 1060 traces a circular orbit with respect to the rotors 114, and without rotating about its geometric center 1082 or otherwise. Alternatively expressed, the synchronizing plate 1060 engages in non-rotative epicyclic oscillation with respect to the 3 rotor shafts 1020 and 3 helical rotors 1000. Accordingly, the rotors 1000 are constrained to rotate in rigid synchronization, thereby enabling inter-rotor gaps on the order of 0.001 inches or less. Further, and in contrast to the gear train and belt/pulley systems of other mechanisms, the synchronizing mechanism 1030 enables such precise synchronization and minute gaps to be maintained over significant duty cycles at high speeds, such as 3600 RPM or higher.

With reference now to FIGS. 10, 13 and 14, a driver crank 1100 includes a driver crankpin lobe 1104 and a driver crankpin 1108 centered on a driver crankpin axis 1112. The driver crankpin lobe 1104 and driver crankpin 1108 are spaced laterally from the driveshaft rotational axis 1116 of the driveshaft 1034 such that the driveshaft rotational axis 1116 is coaxial with the central axis 1016 of the 3-rotor planetary rotor machine. The driver crankpin 1108 is rotatably coupled to a central bearing 1130 of the synchronizing plate 1060.

Further and with reference to FIGS. 12 and 14, the synchronizing mechanism 1030 is configured such that the radius of each rotor crankpin axis 1054 relative to the rotor rotational axis 1028 of the corresponding rotor 1000 is equal to the radius of the driveshaft crankpin axis 1112 relative to the driveshaft rotational axis 1116. Accordingly, the throw of driver crank 1100 is equal to the throw of each rotor crank arm 1044.

With reference now to FIG. 15, in another example of a synchronizing mechanism for a 3-rotor planetary rotor machine, synchronizing mechanism 1030′ includes angled rotor crank arms 1500 having a spacer neck 1520 that provides an additional offset for the synchronizing plate 1060 in the z-axis direction from the rotor crank arms. As shown in the example of FIG. 15, angled rotor crank arms 1500 include a spacer neck 1520 that is angled with respect to a plane of rotation 1530 of the rotor crank arms. The spacer neck 1520 connects a rotor crank base portion 1534 at the rotor rotational axis 1540 with the distal end of the rotor crank arm 1500. As with the synchronizing mechanism 1030 described above and shown in FIG. 10, rotor crankpins 1550 located at the distal end of the 3 rotor crank arms 1500 are rotatably coupled to 3 rotor crank bearings 1078 that are symmetrically oriented around the geometric center 1082 of the synchronizing plate 1060 at 120 degree intervals. A driver crank 1100′ is rotatably coupled to a central bearing in the center of the synchronizing plate 1060. A driveshaft 1034 is fixedly coupled to the driver crank 1100′ and located coaxial with the central axis of the planetary rotor machine.

As described above, the offset geometry of the spacer necks 1520 of the angled rotor crank arms 1500 enables increased crank throw length by allowing the distal end of each arm to clear adjacent rotor rotational axes 1540 and adjacent rotor cranks. Advantageously, greater crank throw length decreases the forces experienced by the 3 rotor crank bearings 1078 of the synchronizing plate 1060.

As with the 4-rotor planetary rotor machine and synchronizing mechanism described above, in other examples of a 3-rotor planetary rotor machine a synchronizing mechanism according to the present disclosure may utilize rotor crank arms having 2 or more angled portions that are each angled with respect to the plane of rotation of the rotor crank arm.

It will be appreciated that the principles of the present disclosure may be utilized with planetary rotor machines including any suitable number of rotors greater than 4 rotors.

It also will be appreciated that references to “one embodiment” or “an embodiment” are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. Unless explicitly stated to the contrary, embodiments “comprising,” “including,” or “having” an element or a plurality of elements having a particular property may include additional such elements not having that property. The terms “including” and “in which” are used as the plain-language equivalents of the respective terms “comprising” and “wherein.” Moreover, the terms “first,” “second,” and “third,” etc. are used merely as labels, and are not intended to impose numerical requirements or a particular positional order on their objects.

The following claims particularly point out certain combinations and sub-combinations regarded as novel and non-obvious. These claims may refer to “an” element or “a first” element or the equivalent thereof. Such claims should be understood to include incorporation of one or more such elements, neither requiring nor excluding two or more such elements. Other combinations and sub-combinations of the disclosed features, functions, elements, and/or properties may be claimed through amendment of the present claims or through presentation of new claims in this or a related application. Such claims, whether broader, narrower, equal, or different in scope to the original claims, also are regarded as included within the subject matter of the present disclosure. 

1. A planetary rotor machine, comprising: a plurality of helical rotors for compressing or expanding a fluid, wherein each of the helical rotors is configured to rotate about a rotor rotational axis, wherein each of the rotor rotational axes is equally spaced from a central axis of the planetary rotor machine; a plurality of rotor shafts, wherein each of the rotor shafts is fixedly coupled to one of the helical rotors and extends axially along the rotor rotational axis; a plurality of rotor cranks, wherein each of the rotor cranks is coupled to one of the rotor shafts, each of the rotor cranks comprising a rotor crank arm that extends away from the rotor rotational axis, each of the rotor crank arms comprising a rotor crankpin at a distal end that is laterally spaced from the rotor rotational axis; a synchronizing plate rotatably coupled to each of the rotor crankpins for non-rotative epicyclic oscillation with respect to the plurality of rotor shafts and the helical rotors; a driver crank rotatably coupled to a central bearing in a geometric center of the synchronizing plate; and a driveshaft fixedly coupled to the driver crank and located coaxial with the central axis of the planetary rotor machine.
 2. The planetary rotor machine of claim 1, wherein the driver crank further comprises a driver crankpin lobe and a driver crankpin that is centered on a driver crankpin axis, the driver crankpin rotatably coupled to the central bearing of the synchronizing plate.
 3. The planetary rotor machine of claim 2, wherein a first radius of the driver crankpin axis relative to the driveshaft rotational axis is equal to a second radius of a rotor crankpin axis relative to the rotor rotational axis for each of the rotor cranks.
 4. The planetary rotor machine of claim 1, wherein each of the rotor cranks has an equal throw, wherein a radius of each rotor crankpin axis relative to the rotor rotational axis is equal for each of the rotor cranks.
 5. The planetary rotor machine of claim 1, wherein each of the rotor crank arms of each of the rotor cranks remains angularly fixed relative to one another during rotation of the helical rotors.
 6. The planetary rotor machine of claim 1, wherein each of the rotor cranks comprises a rotor crank counterweight lobe spaced laterally from the rotor rotational axis and located opposite to the rotor crank arm.
 7. The planetary rotor machine of claim 6, further comprising a rotor crank counterweight coupled to the rotor crank counterweight lobe.
 8. The planetary rotor machine of claim 1, wherein each of the rotor crank arms comprises a straight neck extending parallel to a plane of rotation of the rotor crank arm and connecting a rotor crank base portion at the rotor rotational axis with the distal end of the rotor crank arm.
 9. The planetary rotor machine of claim 1, wherein each of the rotor crank arms comprises a spacer neck that is angled with respect to a plane of rotation of the rotor crank arm and connects a rotor crank base portion at the rotor rotational axis with the distal end of the rotor crank arm.
 10. The planetary rotor machine of claim 9, wherein the spacer neck comprises 2 or more angled portions that are each angled with respect to the plane of rotation of the rotor crank arm and connect the rotor crank base portion at the rotor rotational axis with the distal end of the rotor crank arm.
 11. The planetary rotor machine of claim 1, wherein the planetary rotor machine utilizes 4 helical rotors and 4 rotor cranks with 4 crankpins, and the synchronizing plate comprises 4 bearings symmetrically oriented around the geometric center of the synchronizing plate at 90 degree intervals, with each of the bearings rotatably coupled to one of the 4 crankpins.
 12. The planetary rotor machine of claim 1, wherein the planetary rotor machine utilizes 3 helical rotors and 3 rotor cranks with 3 crankpins, and the synchronizing plate comprises 3 bearings symmetrically oriented around the geometric center of the synchronizing plate at 120 degree intervals, with each of the bearings rotatably coupled to one of the 3 crankpins.
 13. A 4-rotor synchronizing mechanism for a 4-rotor planetary rotor machine, the 4-rotor planetary rotor machine comprising 4 helical rotors for compressing or expanding a fluid and 4 rotor shafts, wherein each of the helical rotors is fixedly coupled to one of the rotor shafts and configured to rotate about a rotor rotational axis, and wherein each of the rotor rotational axes is equally spaced from a central axis of the 4-rotor planetary rotor machine, the 4-rotor synchronizing mechanism comprising: 4 rotor cranks that are each coupled to one of the 4 rotor shafts, each of the rotor cranks comprising a rotor crank arm that extends away from the rotor rotational axis, each of the rotor crank arms comprising a rotor crankpin at a distal end that is laterally spaced from the rotor rotational axis; a synchronizing plate comprising 4 bearings symmetrically oriented around a geometric center of the synchronizing plate at 90 degree intervals, with each of the bearings rotatably coupled to one of the 4 crankpins for non-rotative epicyclic oscillation of the synchronizing plate with respect to the 4 rotor shafts and the 4 helical rotors; a driver crank rotatably coupled to a central bearing in the geometric center of the synchronizing plate; and a driveshaft fixedly coupled to the driver crank and located coaxial with the central axis of the planetary rotor machine.
 14. The 4-rotor synchronizing mechanism of claim 13, wherein each of the rotor crank arms comprises a straight neck extending parallel to a plane of rotation of the rotor crank arm and connecting a rotor crank base portion at the rotor rotational axis with the distal end of the rotor crank arm.
 15. The 4-rotor synchronizing mechanism of claim 13, wherein each of the rotor crank arms comprises a spacer neck that is angled with respect to a plane of rotation of the rotor crank arm and connects a rotor crank base portion at the rotor rotational axis with the distal end of the rotor crank arm.
 16. The 4-rotor synchronizing mechanism of claim 15, wherein the spacer neck comprises 2 or more angled portions that are each angled with respect to the plane of rotation of the rotor crank arm and connect the rotor crank base portion at the rotor rotational axis with the distal end of the rotor crank arm.
 17. A 3-rotor synchronizing mechanism for a 3-rotor planetary rotor machine, the 3-rotor planetary rotor machine comprising 3 helical rotors for compressing or expanding a fluid and 3 rotor shafts, wherein each of the helical rotors is fixedly coupled to one of the rotor shafts and configured to rotate about a rotor rotational axis, and wherein each of the rotor rotational axes is equally spaced from a central axis of the 3-rotor planetary rotor machine, the 3-rotor synchronizing mechanism comprising: 3 rotor cranks that are each coupled to one of the 3 rotor shafts, each of the rotor cranks comprising a rotor crank arm that extends away from the rotor rotational axis, each of the rotor crank arms comprising a rotor crankpin at a distal end that is laterally spaced from the rotor rotational axis; a synchronizing plate comprising 3 bearings symmetrically oriented around a geometric center of the synchronizing plate at 120 degree intervals, with each of the bearings rotatably coupled to one of the 3 crankpins for non-rotative epicyclic oscillation of the synchronizing plate with respect to the 3 rotor shafts and the 3 helical rotors; a driver crank rotatably coupled to a central bearing in the geometric center of the synchronizing plate; and a driveshaft fixedly coupled to the driver crank and located coaxial with the central axis of the planetary rotor machine.
 18. The 3-rotor synchronizing mechanism of claim 17, wherein each of the rotor crank arms comprises a straight neck extending parallel to a plane of rotation of the rotor crank arm and connecting a rotor crank base portion at the rotor rotational axis with the distal end of the rotor crank arm.
 19. The 3-rotor synchronizing mechanism of claim 17, wherein each of the rotor crank arms comprises a spacer neck that is angled with respect to a plane of rotation of the rotor crank arm and connects a rotor crank base portion at the rotor rotational axis with the distal end of the rotor crank arm.
 20. The 3-rotor synchronizing mechanism of claim 19, wherein the spacer neck comprises 2 or more angled portions that are each angled with respect to the plane of rotation of the rotor crank arm and connect the rotor crank base portion at the rotor rotational axis with the distal end of the rotor crank arm. 